JP4774094B2 - Al alloy reflective film for optical information recording for laser marking, optical information recording medium, and Al alloy sputtering target for formation of Al alloy reflective film for optical information recording - Google Patents

Abstract

There are provided an aluminum-alloy reflection film for optical information-recording, having low thermal conductivity, low melting temperature, and high corrosion resistance, capable of coping with laser marking, an optical information-recording medium comprising the reflection film described, and an aluminum-alloy sputtering target for formation of the reflection film described. The invention includes (1) an aluminum-alloy reflection film for optical information-recording, containing an element Al as the main constituent, 1.0 to 10.0 at. % of at least one element selected from the group of rare earth elements, and 0.5 to 5.0 at. % of at least one element selected from the group consisting of elements Cr, Ta, Ti, Mo, V, W, Zr, Hf, Nb, and Ni, (2) an optical information-recording medium comprising any of the aluminum-alloy reflection films described as above, and (3) a sputtering target having the same composition as that for any of the aluminum-alloy reflection films described as above.

Description

The present invention belongs to a technical field related to an Al alloy reflective film for optical information recording for laser marking (use for laser marking) , an optical information recording medium, and an Al alloy sputtering target for forming an Al alloy reflective film for optical information recording. In particular, in order to enable marking using a laser after forming a disk on an optical information recording medium such as a CD, DVD, Blu-ray Disk, HD-DVD, etc., especially on a read-only medium (ROM), A reflective film having low thermal conductivity, low melting temperature, high corrosion resistance and high reflectivity, a sputtering target for forming the reflective film, and an optical information recording medium provided with the reflective film It is.

  There are several types of optical discs, but they are roughly classified into three types: read-only, write-once type, and rewritable type based on the recording and playback principle.

  Among these, as shown in FIG. 1, the read-only disk is a reflective film layer having Al, Ag, Au, etc. as a base material after recording data is formed at the time of manufacture by uneven pits provided on a transparent plastic substrate. The data is reproduced by detecting the phase difference and reflection difference of the laser light irradiated on the disk when reading data. There is also a type that reads out data recorded in two layers by laminating two base materials, each of which has a recording film formed on each recording pit and a base material provided with a reflective film layer and a base material provided with a translucent reflective layer. . In this single-sided recording / reproducing system, data is read-only (not writable or changeable), and CD-ROM, DVD-ROM, BD-ROM, HD-DVD-ROM, etc. are listed as optical disks using this system. . 1 is a schematic diagram showing a cross-sectional structure. In FIG. 1, reference numeral 1 is a polycarbonate substrate, 2 is a translucent reflective layer (Au, Ag alloy, Si), 3 is an adhesive layer, and 4 is a whole layer. Reflective film layers (Al alloy) and 5 are UV curable resin protective layers.

  In such a read-only optical disk, it is difficult to attach an ID to each disk because the disk is mass-produced by press working with a stamper in which an information pattern is formed in advance when the disk is formed. However, for the purpose of preventing unauthorized copying of discs, improving the traceability of product distribution, and improving added value, a dedicated device such as a level gate method or BCA (Burst Cutting Area) method is also used for read-only optical discs after disc formation. Discs that record the ID of each disc using are being standardized. The ID marking is currently performed by a method in which recording is performed mainly by irradiating a manufactured disc with laser light, melting the Al alloy of the reflective film, and making a hole in the reflective film.

  As a reflective film for read-only optical discs, a large amount of general structural material has been distributed so far, and therefore, Al alloys centered on inexpensive JIS6061 (Al-Mg alloy) have been widely used.

  However, since the 6061-based Al alloy is not a material premised on laser marking, problems remain in the following points [1] to [2].

  [1] High thermal conductivity. That is, in order to perform laser marking at a lower output, the thermal conductivity of the reflective film is preferably as low as possible, but the thermal conductivity of the 6061 series Al alloy is too high. For this reason, when laser marking is performed using the current 6061 series Al alloy, there is a problem that the polycarbonate substrate and the adhesive layer constituting the disk are damaged by heat due to excessive laser output.

  [2] Low corrosion resistance. That is, when laser marking is performed, cavities are formed after marking, and therefore, corrosion of the Al alloy film occurs in the subsequent constant temperature and humidity test.

Regarding the reduction of the thermal conductivity of the Al alloy reflective film, in the field of reflective films for magneto-optical recording, for example, in Japanese Patent Laid-Open No. 4-177639 (Patent Document 1), Nb, Ti, Ta, W, Mn is added to Al. A method of reducing thermal conductivity by adding Mo, Mo, etc. is shown. Japanese Patent Laid-Open No. 5-12733 (Patent Document 2) shows a method for reducing the thermal conductivity by adding at least one of Si, Ti, Ta, Cr, Zr, Mo, Pd, and Pt to Al. Has been. JP-A-7-11426 (Patent Document 3) also discloses an alloy film in which W or Y is added to Al. However, these reflective films do not assume that the film is melted or removed by laser irradiation, so the thermal conductivity of the film decreases, but at the same time the melting temperature increases or after marking as described above. The problem of the corrosion of the cavity is not taken into consideration, and an Al alloy for laser marking that satisfies the requirements has not yet been provided.
Japanese Patent Laid-Open No. 4-177393 JP-A-5-12733 Japanese Patent Laid-Open No. 7-11426

  As described above, the Al alloy corresponding to the laser marking is required to have low thermal conductivity, low melting temperature, and high corrosion resistance.

  However, as described above, the 6061 Al alloy used as a reflective film in a read-only optical disk has high thermal conductivity and low corrosion resistance, which makes it difficult to support laser marking applications. is there. Further, in the field of magneto-optical recording reflective films, Al alloys that have been proposed so far (as described in Patent Documents 1 to 3) are difficult to handle for laser marking as described above.

  The present invention has been made paying attention to such circumstances, and its purpose is to have a low thermal conductivity, a low melting temperature, a high corrosion resistance, and an Al alloy reflection for optical information recording that can be applied to laser marking. It is intended to provide a film, an optical information recording medium provided with the reflective film, and a sputtering target for forming the reflective film.

  As a result of intensive studies to achieve the above object, the present inventors have found that an Al alloy thin film containing a specific amount of a specific alloy element with respect to Al has low thermal conductivity, low melting temperature, and high corrosion resistance. In addition, the inventors have found that the film is a reflective thin film layer (metal thin film layer) suitable as a reflective film for optical information recording suitable for laser marking. This invention is made | formed based on such knowledge, According to this invention, the said objective can be achieved.

The present invention, which has been completed in this way and has achieved the above object, is an Al alloy reflective film for optical information recording for laser marking , an optical information recording medium, and Al alloy for forming an Al alloy reflective film for optical information recording. 5. An optical information recording Al alloy reflective film for optical information recording according to claims 1 to 3 (Al alloy reflective film according to the first to third inventions) according to claims 1 to 3, and an optical information recording medium according to claim 4 An optical information recording medium according to a fourth aspect of the present invention is an Al alloy sputtering target (sputtering target according to the fifth aspect ) for forming an Al alloy reflective film for optical information recording according to claim 5 , which has the following configuration It is what.

That is, the Al alloy reflective film for optical information recording according to claim 1 is an Al alloy reflective film that is used in an optical information recording medium and is laser-marked , comprising Al as a main component, Nd and / or Y For laser marking , characterized by containing 1.0 to 10.0 atomic%, and further containing 0.5 to 5.0 atomic% of at least one of Cr , Ti , Mo, V, W, Zr, Hf, Nb, and Ni . An Al alloy reflective film for optical information recording [first invention].

The Al alloy reflective film for optical information recording according to claim 2 is the Al alloy reflective film for optical information recording according to claim 1, wherein the Nd and / or Y content is 2.0 to 7.0 atomic% . invention〕.

The Al alloy reflective film for optical information recording according to claim 3, wherein the content of at least one of Cr, Ti, Mo, V, W, Zr, Hf, Nb, and Ni is 2.0 to 4.0 atomic%. 3. An Al alloy reflective film for optical information recording according to 1 or 2 [third invention].

An optical information recording medium according to claim 4 is an optical information recording medium comprising the Al alloy reflective film according to any one of claims 1 to 3 [ fourth invention].

An Al alloy sputtering target for forming an Al alloy reflective film for optical information recording according to claim 5 is used for an optical information recording medium and used for forming an Al alloy reflective film to be laser-marked. In addition, Al is the main component, Nd and / or Y is contained in 1.0 to 10.0 atomic%, and at least one of Cr , Ti , Mo, V, W, Zr, Hf, Nb, and Ni is contained in 0.5 to 5. An Al alloy sputtering target for forming an Al alloy reflective film for optical information recording for laser marking characterized by containing 0 atomic% [ fifth invention].

  The Al alloy reflective film for optical information recording according to the present invention can have a low thermal conductivity, a low melting temperature, and a high corrosion resistance, and can be suitably used as a reflective film for optical information recording that can cope with laser marking. . The optical information recording medium according to the present invention has such an Al alloy reflective film and can suitably perform laser marking. According to the Al alloy sputtering target for forming an Al alloy reflective film for optical information recording according to the present invention, such an Al alloy reflective film can be formed.

  As described above, an Al alloy thin film suitable for laser marking needs to have a low thermal conductivity, a low melting temperature, and a high corrosion resistance.

  The present inventors manufactured Al alloy sputtering targets in which various elements were added to Al, and formed Al alloy thin films having various components and compositions by sputtering using these targets. As a result, the following [1) to (5)] were found.

(1) By adding 1.0 to 10.0 atomic% (at%) in total of Nd and / or Y to Al, the thermal conductivity can be greatly reduced without increasing the melting temperature (liquidus temperature). When the amount of Nd and / or Y added is less than 1.0 at%, the effect of reducing the thermal conductivity is small. When the amount of Nd and / or Y added exceeds 10.0 at%, the reflectance is greatly reduced . Na us, with respect to corrosion resistance, it is not sufficient to only the addition of Nd and / or Y.

(2) As described above, Nd and / or Y is added to Al in a total amount of 1.0 to 10.0 at%, and at least one of Cr , Ti , Mo, V, W, Zr, Hf, Nb, and Ni is added. Corrosion resistance can be greatly improved by adding 0.5 to 5.0 at% in total. Moreover, these elements [Cr , Ti , Mo, V, W, Zr, Hf, Nb, Ni (hereinafter also referred to as Cr to Nb, Ni)] also lower the thermal conductivity. However, these elements (Cr to Nb, Ni) greatly increase the melting temperature (liquidus temperature) and lower the reflectivity, so the amount of addition is limited and it is necessary to make it 5.0% or less. . Preferably it is 3.0 at% or less. When the added amount of these elements (Cr to Nb, Ni) is less than 0.5 at%, the corrosion resistance improving effect is small. Preferably it is 1.0 at% or more. Among these elements, it is preferable to select Cr, Ta, Ti, and Hf because the effect of improving the corrosion resistance is particularly great.

(3) As described above (as described in (2) above), Nd and / or Y is added to Al in a total amount of 1.0 to 10.0 at%, and at least one of Cr to Nb and Ni is added to a total of 0.5 to The thermal conductivity can be reduced by adding 5.0 at% and further adding 1.0 to 5.0 at% in total of at least one of Fe and Co. When the added amount of these elements (Fe, Co) is less than 1.0 at%, the effect of reducing the thermal conductivity is small, and in order to fully exhibit the effect of reducing the thermal conductivity, these elements (Fe , Co) should be added at 1.0 at% or more. If these elements (Fe, Co) are added too much, the reflectivity will decrease, and the sputtering target will be easily manufactured. Therefore, the amount of these elements (Fe, Co) added is 5.0 at% or less. It is good to do.

(4) As described above (as described in (2) above), Nd and / or Y is added to Al in a total amount of 1.0 to 10.0 at%, and at least one of Cr to Nb and Ni is added in a total amount of 0.5 to By adding 5.0 at% and further adding at least one of In, Zn, Ge, Cu, and Li in a total amount of 1.0 to 10.0 at%, the thermal conductivity and the melting temperature can be reduced. When the added amount of these elements [In, Zn, Ge, Cu, Li (hereinafter also referred to as In to Li)] is less than 1.0 at%, the effect of reducing the thermal conductivity and the effect of reducing the melting temperature are small. In order to sufficiently exhibit the effect of reducing the thermal conductivity and the effect of reducing the melting temperature, it is preferable to add these elements (In to Li) in an amount of 1.0 at% or more. If these elements (In to Li) are added too much, the reflectivity will decrease greatly. Therefore, the amount of these elements (In to Li) added should be 10.0 at% or less.

(5) As described above (as described in (2) above), Nd and / or Y is added to Al in a total amount of 1.0 to 10.0 at%, and at least one of Cr to Nb and Ni is added to a total of 0.5 to The melting temperature can be reduced by adding 5.0 at% and further adding at least one of Si and Mg by 5.0 at% or less. Of these elements (Si, Mg), Si also has an effect of improving corrosion resistance. Note that these elements (Si, Mg) have no effect of reducing thermal conductivity. In order to sufficiently exhibit the effect of reducing the melting temperature, it is desirable to add 1.0 at% or more of these elements (Si, Mg). If it is added too much, the reflectivity is lowered, and it is preferable to set the content to 5.0 at% or less from the viewpoint of easy target production.

  Based on the above findings, the present invention has been completed, and is used for forming an Al alloy reflective film for optical information recording, an optical information recording medium, and an Al alloy reflective film for optical information recording having the above-described configuration. Al alloy sputtering target.

The optical information recording Al alloy reflective film according to the present invention thus has been completed, used in an optical information recording medium, and a Al alloy reflective film which is laser marking, as a main component Al, Nd And / or Y is contained in an amount of 1.0 to 10.0 atom%, and at least one of Cr to Nb, Ni (Cr , Ti , Mo, V, W, Zr, Hf, Nb, Ni) is contained in an amount of 0.5 to 5.0 atom%. It is an Al alloy reflective film for optical information recording for laser marking characterized by containing [first invention].

As can be seen from the above (1) to (2), this Al alloy reflective film for optical information recording contains Nd and / or Y in a total amount of 1.0 to 10.0 at%, so that the melting temperature (liquidus) The thermal conductivity can be greatly reduced without increasing the temperature), and the corrosion resistance can be greatly improved by containing 0.5 to 5.0 at% of at least one of Cr to Nb and Ni, and the thermal conductivity can be reduced. Further reduction can be achieved.

  Therefore, the Al alloy reflective film for optical information recording according to the present invention can have low thermal conductivity, low melting temperature, and high corrosion resistance, can cope with laser marking well, and is suitably used as a reflective film for optical information recording. be able to. That is, since the melting temperature is low, the laser marking can be facilitated, and since the thermal conductivity is low, the laser output may be low during laser marking (there is no need to make the laser output excessive). Therefore, the thermal damage of the disk components (polycarbonate substrate and adhesive layer) due to excessive laser output does not occur, and it has excellent corrosion resistance. Corrosion in the constant temperature and humidity test after laser marking (Corrosion of the Al alloy reflecting film due to the moisture to be generated) can be prevented.

When the Al alloy reflective film for optical information recording according to the present invention further contains 1.0 to 5.0 at% of at least one of Fe and Co, as can be seen from the above (3), the thermal conductivity is It can be greatly reduced .

When the Al alloy reflective film for optical information recording according to the present invention further contains 1.0 to 10.0 at% of at least one of In to Li (In, Zn, Ge, Cu, Li), (4) As can be seen from the above, the melting temperature can be reduced, and the thermal conductivity can be further reduced .

When the Al alloy reflective film for optical information recording according to the present invention further contains 5.0 atomic% or less of at least one of Si and Mg, as can be seen from the above (5), the melting temperature is Can be reduced . Of these elements (Si, Mg), Si also has the effect of improving the corrosion resistance.

  In the present invention, the thickness of the Al alloy reflective film for optical information recording is desirably 30 nm to 200 nm. This is because laser marking is easier when the film thickness is thinner, but when the film thickness is less than 30 nm, light is transmitted and the reflectance decreases, while the film thickness increases. At the same time, the surface smoothness is lowered and light is easily scattered, and light scattering tends to occur when the film thickness exceeds 200 nm. From the viewpoint of suppressing the reflectance and light scattering, it is further desirable to set the film thickness to 40 to 100 nm.

The optical information recording medium according to the present invention includes the Al alloy reflective film for optical information recording according to the present invention as described above [ fourth invention]. This optical information recording medium can suitably perform laser marking. For this reason, there is no thermal damage to the disk components (polycarbonate substrate and adhesive layer) due to excessive laser output, and the corrosion resistance of the Al alloy reflective film is excellent, so corrosion (laser in a constant temperature and humidity test after laser marking) Corrosion of the Al alloy reflecting film due to moisture entering the cavities after marking is unlikely to occur, and excellent characteristics can be obtained in this respect.

Since the optical information recording medium according to the present invention can have excellent characteristics as described above, it can be particularly suitably used for laser marking .

An Al alloy sputtering target according to the present invention is an Al alloy sputtering target used for an optical information recording medium and used for forming an Al alloy reflective film to be laser-marked, comprising Al as a main component, Nd and / or Alternatively, Y is contained in an amount of 1.0 to 10.0 atomic% and at least one of Cr to Nb and Ni (Cr , Ti , Mo, V, W, Zr, Hf, Nb, Ni) is contained in an amount of 0.5 to 5.0 atomic%. An Al alloy sputtering target for forming an Al alloy reflective film for optical information recording for laser marking [ fifth invention]. According to this Al alloy sputtering target, the Al alloy reflective film for optical information recording according to the first invention of the present invention can be formed.

  Examples of the present invention and comparative examples will be described below. The present invention is not limited to this embodiment, and can be implemented with appropriate modifications within a range that can be adapted to the gist of the present invention, all of which are within the technical scope of the present invention. include.

[Example 1]
Al-Nd (Nd-containing Al alloy) thin film and Al-Y (Y-containing Al alloy) thin film were prepared, Nd, Y addition amount (content), thin film melting temperature, thermal conductivity The relationship between reflectance and BCA (Burst Cutting Area) characteristics was investigated.

The thin film was produced as follows. That is, an Al—Nd thin film or an Al—Y thin film was formed (film formation) on a glass substrate (Corning # 1737, substrate size: diameter 50 mm, thickness 1 mm) by DC magnetron sputtering. At this time, the film forming conditions are: substrate temperature: 22 ° C., Ar gas pressure: 2 mTorr, film forming speed: 2 nm / sec, back pressure: <5 × 10 ⁻⁶ Torr. As the sputtering target, an Al alloy sputtering target having the same composition as the Al alloy thin film to be obtained was used.

  The melting temperature of the thin film was measured as follows. An Al alloy thin film (Al—Nd thin film, Al—Y thin film) formed to a thickness of 1 μm was peeled off from the substrate, and about 5 mg collected was measured using a differential calorimeter. At this time, the average value of the melting end temperature at the time of temperature rise and the temperature at which the solidification starts at the time of temperature fall was defined as the melting temperature. About thermal conductivity, it converted from the electrical resistivity of the Al alloy thin film produced by thickness 100nm. The reflectivity was obtained by preparing an Al alloy thin film with a thickness of 100 nm and measuring the reflectivity at wavelengths of 650 nm and 405 nm used in the current DVD.

   Regarding the BCA characteristics, the film formation conditions were the same as described above, but an experiment was performed by using a PC (polycarbonate) substrate having a thickness of 0.6 mm and producing an Al alloy thin film having a thickness of 70 nm. In the experiment, the thin film was irradiated with laser (laser marking) under the laser conditions of laser wavelength: 810 nm, linear velocity: 4 m / sec, laser power: 1.5 W, and the characteristics were evaluated by the aperture ratio of the laser marking portion. For evaluation, a BCA code recording device for DVD-ROM POP120-8R (manufactured by Hitachi Computer Equipment) was used. In the evaluation of BCA characteristics described later, those with an aperture ratio of 95% or more are marked with ◎, those with an aperture ratio of 80% or more and less than 95%, ○, those with an aperture ratio of 50% or more and less than 80%, and aperture ratio. Is less than 50%.

  On the other hand, as a comparative material for the Al alloy thin film (Al—Nd thin film, Al—Y thin film), an Al alloy thin film having a composition corresponding to the JIS6061 material was produced (formed) by the same method as described above. At this time, an Al alloy target produced from JIS6061 material was used as the sputtering target. This composition contains Si: 0.75 wt% (mass%), Fe: 0.10 wt%, Cu: 0.41 wt%, Mn: 0.07 wt%, Mg: 1.10 wt%, Cr: 0.12 wt%, the balance being Al And inevitable impurities. The composition of the produced Al alloy thin film is the same as the composition of the Al alloy target.

  And about the Al alloy thin film of the composition corresponded to this JIS6061 material, the melting temperature, the electrical resistivity, the thermal conductivity, the reflectance, and the BCA characteristic were measured by the same method as described above.

  The results of the above measurement (survey) are shown in Table 1. In Table 1, the Nd amount and Y amount of Al-Nd and Al-Y in the composition column are values in at% (atomic%). That is, Al-X · Nd is an Al alloy (Al-Nd alloy) thin film containing X at% Nd, and Al-X · Y is an Al alloy (Al-Y alloy) containing X at% Y. It is a thin film. For example, Al-1.0Nd is an Al alloy containing 1.0 at% Nd.

  As can be seen from Table 1, the thermal conductivity greatly decreases with increasing Nd amount and Y amount. On the other hand, the melting temperature hardly changes even if the Nd amount and the Y amount increase. Further, the reflectance gradually decreases as the Nd amount and the Y amount increase.

  Regarding the thermal conductivity, a sufficiently good value (low value) is obtained when the Nd content and the Y content are 1.0 at% or more, and an even higher value is obtained when it is 2.0 at% or more. Regarding the reflectance, when the Nd amount and the Y amount are 10.0 at% or less, they are sufficiently good values (high values). However, in this range, when it exceeds 7 at%, the degree of decrease in reflectance is larger than that when it is 7 at% or less.

  From these results, it can be seen that the added amount (content) of the Nd amount and the Y amount needs to be 1.0 to 10.0 at%, and more preferably 2.0 to 7 at%.

[Example 2]
Al-4.0Nd- (Cr, Ti) thin film (with containing Nd 4.0 at%, Cr, thin film made of an Al alloy containing one or more of Ti) was prepared, Cr, the addition amount of Ti and the thin film The relationship between melting temperature, thermal conductivity, reflectance, corrosion resistance and BCA properties was investigated.

The thin film was produced as follows. That is, an Al-4.0Nd- ( Cr , Ti) alloy thin film was formed (film formation) on a glass substrate (Corning # 1737, substrate size: diameter 50 mm, thickness 1 mm) by DC magnetron sputtering. At this time, the film forming conditions are: substrate temperature: 22 ° C., Ar gas pressure: 2 mTorr, film forming speed: 2 nm / sec, back pressure: <5 × 10 ⁻⁶ Torr. As the sputtering target, an Al alloy sputtering target having the same composition as the Al alloy thin film to be obtained was used.

The melting temperature of the thin film was measured as follows. An Al alloy thin film [Al-4.0Nd- (Cr, Ti) thin film] formed to a thickness of 1 μm was peeled from the substrate, and about 5 mg collected was measured using a differential calorimeter. At this time, the average value of the melting end temperature at the time of temperature rise and the temperature at which the solidification starts at the time of temperature fall was defined as the melting temperature. About thermal conductivity, it converted from the electrical resistivity of the Al alloy thin film produced by thickness 100nm. The reflectance was obtained by preparing an Al alloy thin film with a thickness of 100 nm and measuring the reflectance at a wavelength of 650 nm and a wavelength of 405 nm used in the current DVD. As for corrosion resistance, anodic polarization measurement was performed by dipping in a 5% NaCl solution at 35 ° C., and from this, the pitting corrosion occurrence potential (potential corresponding to a current density of 10 μA / cm ² ) was obtained and used as an index of corrosion resistance. This potential is a potential based on a saturated calomel electrode (SCE), that is, a potential with respect to the SCE potential (hereinafter the same).

   Regarding the BCA characteristics, the film formation conditions were the same as described above, but an experiment was performed by using a PC (polycarbonate) substrate having a thickness of 0.6 mm and producing an Al alloy thin film having a thickness of 70 nm. In the experiment, the thin film was irradiated with laser (laser marking) under the laser conditions of laser wavelength: 810 nm, linear velocity: 4 m / sec, laser power: 1.5 W, and the characteristics were evaluated by the aperture ratio of the laser marking portion. For evaluation, a BCA code recording device for DVD-ROM POP120-8R (manufactured by Hitachi Computer Equipment) was used. In the evaluation of BCA characteristics described later, those with an aperture ratio of 95% or more are marked with ◎, those with an aperture ratio of 80% or more and less than 95%, ○, those with an aperture ratio of 50% or more and less than 80%, and aperture ratio. Is less than 50%.

The results of the above measurement (survey) are shown in Table 2. In Table 2, the Nd amount , Cr amount, and Ti amount of Al-4Nd- ( Cr , Ti) in the composition column are values in at% (atomic%). That is, Al-4Nd—Y · Cr (or Ti) contains 4.0 at% Nd and Y at% Cr (or Ti) Al alloy [Al-Nd- (Cr, Ti) alloy] It is a thin film .

As can be seen from Table 2, the potential of pitting corrosion increases (becomes noble) with increasing amounts (contents) of Ti and Cr, and the corrosion resistance is improved . Hand, these elements (Ti, Cr) with increasing amount of increased melt temperature, The reflectance is lowered.

Corrosion resistance is sufficiently good (high value) when the Ti content and Cr content are 0.5 at% or more, and is at a higher level when 2.0 Ti % or more. The reflectivity is sufficiently good (high value) when the Ti content and Cr content are 5.0 at% or less, and is at a higher level when it is 4.0 at% or less. Regarding the melting temperature, it is a sufficiently good value (low value) when the Ti content and Cr content are 5.0 at% or less, and a higher level of good value when it is 4.0 at% or less.

From these results, it is understood that the addition amount (content) of Ti amount and Cr amount should be 0.5 to 5.0 at%, and more preferably 2.0 to 4.0 at%.

  As can be seen from Tables 1 and 2, the film made of pure Al has a large thermal conductivity and is not good, and the pitting corrosion occurrence potential is low (base) and the corrosion resistance is not good. For the Al alloy film having a composition corresponding to JIS6061 material, the pitting corrosion occurrence potential is not shown in the table, but it is -744 mV, and the pitting corrosion occurrence potential is low and the corrosion resistance is not good.

[Example 3]
Al-4.0Nd- [Mo, V, W, Zr, Hf, Nb, Ni (hereinafter also referred to as Mo to Nb, Ni)] thin film (containing 4.0 at% of Nd and one of Mo to Nb, Ni) A thin film made of an Al alloy containing the above was prepared, and the relationship between the addition amount of Mo to Nb and Ni and the melting temperature, thermal conductivity, reflectance, corrosion resistance and BCA characteristics of the thin film was investigated.

The thin film was produced as follows. That is, an Al-4.0Nd- (Mo to Nb, Ni) alloy thin film was formed (film formation) on a glass substrate (Corning # 1737, substrate size: diameter 50 mm, thickness 1 mm) by DC magnetron sputtering. At this time, the film forming conditions are: substrate temperature: 22 ° C., Ar gas pressure: 2 mTorr, film forming speed: 2 nm / sec, back pressure: <5 × 10 ⁻⁶ Torr. As the sputtering target, an Al alloy sputtering target having the same composition as the Al alloy thin film to be obtained was used.

The melting temperature of the thin film was measured as follows. An Al alloy thin film [Al-4.0Nd- (Mo to Nb, Ni) thin film] formed to a thickness of 1 μm was peeled from the substrate, and about 5 mg collected was measured using a differential calorimeter. At this time, the average value of the melting end temperature at the time of temperature rise and the temperature at which the solidification starts at the time of temperature fall was defined as the melting temperature. About thermal conductivity, it converted from the electrical resistivity of the Al alloy thin film produced by thickness 100nm. The reflectance was obtained by preparing an Al alloy thin film with a thickness of 100 nm and measuring the reflectance at a wavelength of 650 nm and a wavelength of 405 nm used in the current DVD. As for corrosion resistance, anodic polarization measurement was performed by dipping in a 5% NaCl solution at 35 ° C., and from this, the pitting corrosion occurrence potential (potential corresponding to a current density of 10 μA / cm ² ) was obtained and used as an index of corrosion resistance.

   Regarding the BCA characteristics, the film formation conditions were the same as described above, but an experiment was performed by using a PC (polycarbonate) substrate having a thickness of 0.6 mm and producing an Al alloy thin film having a thickness of 70 nm. In the experiment, the thin film was irradiated with laser (laser marking) under the laser conditions of laser wavelength: 810 nm, linear velocity: 4 m / sec, laser power: 1.5 W, and the characteristics were evaluated by the aperture ratio of the laser marking portion. For evaluation, a BCA code recording device for DVD-ROM POP120-8R (manufactured by Hitachi Computer Equipment) was used. In the evaluation of BCA characteristics described later, those with an aperture ratio of 95% or more are marked with ◎, those with an aperture ratio of 80% or more and less than 95%, ○, those with an aperture ratio of 50% or more and less than 80%, and aperture ratio. Is less than 50%.

  The results of the above measurement (investigation) are shown in Tables 3-4. In Tables 3 to 4, the amounts of Mo to Nb and Ni of Al-4Nd- (Mo to Nb, Ni) in the composition column are values in at% (atomic%). That is, Al-4Nd-Y.Mo (or one of V to Nb, Ni) contains 4.0 at% Nd and Y at% Mo (or one of V to Nb, Ni). Al alloy [Al-Nd- (Mo to Nb, Ni) alloy] thin film. For example, Al-4Nd-1.0Mo is an Al alloy containing 4.0 at% Nd and 1.0 at% Mo.

  As can be seen from Tables 3 to 4, Mo to Nb and Ni (Mo, V, W, Zr, Hf, Nb, and Ni) all increase in pitting corrosion potential as the amount (content) increases. (Become noble) and improve corrosion resistance. On the other hand, as the addition amount of these elements (Mo to Nb, Ni) increases, the melting temperature increases and the reflectance decreases.

  Regarding the corrosion resistance, a sufficiently good value (high value) is obtained when the added amount of Mo to Nb, Ni is 0.5 at% or more, and a higher level of good value is obtained when the addition amount is 2.0 at% or more. As for the reflectance, a sufficiently good value (high value) is obtained when the addition amount of Mo to Nb, Ni is 5.0 at% or less, and a higher level of good value is obtained when it is 4.0 at% or less. Regarding the melting temperature, a sufficiently good value (low value) is obtained when the amount of addition of Mo to Nb and Ni is 5.0 at% or less, and an even higher level of good value when 4.0 at% or less.

  From these, it can be seen that the addition amount (content) of Mo to Nb and Ni needs to be 0.5 to 5.0 at%, and more preferably 2.0 to 4.0 at%.

[Example 4]
Al-4.0Nd- (Fe, Co) thin film (thin film containing 4.0 at% Nd and made of Al alloy containing Fe or Co) and Al-4.0Nd-1Ta- (Fe, Co) thin film ( A thin film made of an Al alloy containing 4.0 at% Nd and 1.0 at% Ta and containing Fe or Co), and the addition amount of Fe and Co and the melting temperature, thermal conductivity, reflectance, Corrosion resistance and BCA properties were investigated.

The thin film was produced as follows. That is, by DC magnetron sputtering, an Al-4.0Nd- (Fe, Co) alloy thin film or Al-4.0Nd-1Ta- (Fe on a glass substrate (Corning # 1737, substrate size: diameter 50 mm, thickness 1 mm). , Co) alloy thin films and the like were produced (film formation). At this time, the film forming conditions are: substrate temperature: 22 ° C., Ar gas pressure: 2 mTorr, film forming speed: 2 nm / sec, back pressure: <5 × 10 ⁻⁶ Torr. As the sputtering target, an Al alloy sputtering target having the same composition as the Al alloy thin film to be obtained was used.

The melting temperature of the thin film was measured as follows. An Al alloy thin film [Al-4.0Nd- (Fe, Co) thin film, Al-4.0Nd-1Ta- (Fe, Co) thin film, etc.] formed to a thickness of 1 μm was peeled from the substrate and collected about 5 mg. Measurement was performed using a differential calorimeter. At this time, the average value of the melting end temperature at the time of temperature rise and the temperature at which the solidification starts at the time of temperature fall was defined as the melting temperature. About thermal conductivity, it converted from the electrical resistivity of the Al alloy thin film produced by thickness 100nm. The reflectance was obtained by preparing an Al alloy thin film with a thickness of 100 nm and measuring the reflectance at a wavelength of 650 nm and a wavelength of 405 nm used in the current DVD. As for corrosion resistance, anodic polarization measurement was performed by dipping in a 5% NaCl solution at 35 ° C., and from this, the pitting corrosion occurrence potential (potential corresponding to a current density of 10 μA / cm ² ) was obtained and used as an index of corrosion resistance.

   Regarding the BCA characteristics, the film formation conditions were the same as described above, but an experiment was performed by using a PC (polycarbonate) substrate having a thickness of 0.6 mm and producing an Al alloy thin film having a thickness of 70 nm. In the experiment, the thin film was irradiated with laser (laser marking) under the laser conditions of laser wavelength: 810 nm, linear velocity: 4 m / sec, laser power: 1.5 W, and the characteristics were evaluated by the aperture ratio of the laser marking portion. For evaluation, a BCA code recording device for DVD-ROM POP120-8R (manufactured by Hitachi Computer Equipment) was used. In the evaluation of BCA characteristics described later, those with an aperture ratio of 95% or more are marked with ◎, those with an aperture ratio of 80% or more and less than 95%, ○, those with an aperture ratio of 50% or more and less than 80%, and aperture ratio. Is less than 50%.

  The results of the above measurement (investigation) are shown in Table 5. In Table 5, the amounts of Fe and Co of Al-4Nd-1Ta- (Fe, Co) in the composition column are values in at%. In other words, Al-4Nd-1Ta—Z · Fe (or Co) contains 4.0 at% Nd and 1.0 at% Ta and an Al alloy containing Z at% Fe (or Co) [Al-Nd -Ta- (Fe, Co) alloy] thin film. For example, Al-4Nd-1Ta-3.0Fe is an Al alloy containing 4.0 at% Nd, 1.0 at% Ta, and 3.0 at% Fe.

  As can be seen from Table 5, both Fe and Co have the effect of lowering the thermal conductivity. Fe and Co have no effect on improving corrosion resistance.

  When the added amount of Fe and Co is less than 1.0 at%, the effect of reducing the thermal conductivity is small. When the added amount of Fe and Co exceeds 5.0 at%, the decrease in reflectance increases. From these, it can be seen that the addition amount of Fe and Co is preferably 1.0 to 5.0 at%.

[Example 5]
Al-4.0Nd- [In-Li (In, Zn, Ge, Cu, Li)] thin film (thin film comprising 4.0 at% of Nd and comprising an Al alloy containing one or more of In-Li), and , Al-4.0Nd-1Ta- [In to Li (In, Zn, Ge, Cu, Li)] thin film (Nd contains 4.0 at%, Ta contains 1.0 at%, and contains one or more of In to Li A thin film made of an Al alloy) was prepared, and the relationship between the addition amount of In to Li and the melting temperature, thermal conductivity, reflectance, corrosion resistance, and BCA characteristics of the thin film was investigated.

The thin film was produced as follows. That is, an Al-4.0Nd- (In to Li) alloy thin film or Al-4.0Nd-1Ta- (In is formed on a glass substrate (Corning # 1737, substrate size: diameter 50 mm, thickness 1 mm) by DC magnetron sputtering. ~ Li) An alloy thin film or the like was produced (film formation). At this time, the film forming conditions are: substrate temperature: 22 ° C., Ar gas pressure: 2 mTorr, film forming speed: 2 nm / sec, back pressure: <5 × 10 ⁻⁶ Torr. As the sputtering target, an Al alloy sputtering target having the same composition as the Al alloy thin film to be obtained was used.

The melting temperature of the thin film was measured as follows. An Al alloy thin film (Al-4.0Nd- (In to Li) thin film, Al-4.0Nd-1Ta- (In to Li) thin film, etc.) formed to a thickness of 1 μm was peeled from the substrate and collected about 5 mg. Measurement was performed using a differential calorimeter. At this time, the average value of the melting end temperature at the time of temperature rise and the temperature at which the solidification starts at the time of temperature fall was defined as the melting temperature. About thermal conductivity, it converted from the electrical resistivity of the Al alloy thin film produced by thickness 100nm. The reflectance was obtained by preparing an Al alloy thin film with a thickness of 100 nm and measuring the reflectance at a wavelength of 650 nm and a wavelength of 405 nm used in the current DVD. As for corrosion resistance, anodic polarization measurement was performed by dipping in a 5% NaCl solution at 35 ° C., and from this, the pitting corrosion occurrence potential (potential corresponding to a current density of 10 μA / cm ² ) was obtained and used as an index of corrosion resistance.

   Regarding the BCA characteristics, the film formation conditions were the same as described above, but an experiment was performed by using a PC (polycarbonate) substrate having a thickness of 0.6 mm and producing an Al alloy thin film having a thickness of 70 nm. In the experiment, the thin film was irradiated with laser (laser marking) under the laser conditions of laser wavelength: 810 nm, linear velocity: 4 m / sec, laser power: 1.5 W, and the characteristics were evaluated by the aperture ratio of the laser marking portion. For evaluation, a BCA code recording device for DVD-ROM POP120-8R (manufactured by Hitachi Computer Equipment) was used. In the evaluation of BCA characteristics described later, those with an aperture ratio of 95% or more are marked with ◎, those with an aperture ratio of 80% or more and less than 95%, ○, those with an aperture ratio of 50% or more and less than 80%, and aperture ratio. Is less than 50%.

  The results of the above measurement (investigation) are shown in Table 6. In Table 6, the amount of In to Li in Al-4Nd-1Ta— (In to Li) in the composition column is a value in at% (atomic%). That is, Al-4Nd-1Ta-Z · In (or one of Zn, Ge, Cu and Li) contains 4.0 at% Nd and 1.0 at% Ta and Z at% In (or Zn, It is an Al alloy [Al-Nd-Ta- (In to Li) alloy] thin film containing Ge, Cu, or Li). For example, Al-4Nd-1Ta-3.0In is an Al alloy containing 4.0 at% Nd, 1.0 at% Ta, and 3.0 at% In.

  As can be seen from Table 6, each of In to Li (In, Zn, Ge, Cu, Li) has the effect of lowering the melting temperature and lowering the thermal conductivity. Among In to Li, In and Ge are particularly effective in reducing the thermal conductivity, and In and Ge are preferably added in this respect. In to Li have no effect of improving corrosion resistance.

  When the addition amount of In to Li is less than 1.0 at%, the effect of reducing the thermal conductivity and the effect of reducing the melting temperature are small. When the addition amount of In to Li exceeds 10.0 at%, the reflectance decreases greatly. From these, it can be seen that the addition amount of In to Li is preferably 1.0 to 10.0 at%.

[Example 6]
An Al-4.0Nd-2.0Ta- (Si, Mg) thin film (a thin film made of an Al alloy containing 4.0 at% Nd and 2.0 at% Ta and containing at least one of Si and Mg) is prepared. The relationship between Si and Mg content and the melting temperature, thermal conductivity, reflectivity, corrosion resistance and BCA characteristics of the thin film was investigated.

The thin film was produced as follows. That is, an Al-4.0Nd-2.0Ta- (Si, Mg) alloy thin film was formed (film formation) on a glass substrate (Corning # 1737, substrate size: diameter 50 mm, thickness 1 mm) by DC magnetron sputtering. At this time, the film forming conditions are: substrate temperature: 22 ° C., Ar gas pressure: 2 mTorr, film forming speed: 2 nm / sec, back pressure: <5 × 10 ⁻⁶ Torr. As the sputtering target, an Al alloy sputtering target having the same composition as the Al alloy thin film to be obtained was used.

The melting temperature of the thin film was measured as follows. An Al alloy thin film [Al-4.0Nd-2.0Ta- (Si, Mg) thin film] formed to a thickness of 1 μm was peeled from the substrate, and about 5 mg collected was measured using a differential calorimeter. At this time, the average value of the melting end temperature at the time of temperature rise and the temperature at which the solidification starts at the time of temperature fall was defined as the melting temperature. About thermal conductivity, it converted from the electrical resistivity of the Al alloy thin film produced by thickness 100nm. The reflectance was obtained by preparing an Al alloy thin film with a thickness of 100 nm and measuring the reflectance at a wavelength of 650 nm and a wavelength of 405 nm used in the current DVD. As for corrosion resistance, anodic polarization measurement was performed by immersing in a 5% NaCl solution at 35 ° C., and a pitting corrosion occurrence potential (potential corresponding to a current density of 10 μA / cm ² ) was obtained from this, and this was used as an index of corrosion resistance.

   Regarding the BCA characteristics, the film formation conditions were the same as described above, but an experiment was performed by using a PC (polycarbonate) substrate having a thickness of 0.6 mm and producing an Al alloy thin film having a thickness of 70 nm. In the experiment, the thin film was irradiated with laser (laser marking) under the laser conditions of laser wavelength: 810 nm, linear velocity: 4 m / sec, laser power: 1.5 W, and the characteristics were evaluated by the aperture ratio of the laser marking portion. For evaluation, a BCA code recording device for DVD-ROM POP120-8R (manufactured by Hitachi Computer Equipment) was used. In the evaluation of BCA characteristics described later, those with an aperture ratio of 95% or more are marked with ◎, those with an aperture ratio of 80% or more and less than 95%, ○, those with an aperture ratio of 50% or more and less than 80%, and aperture ratio. Is less than 50%.

  Table 7 shows the results of the above measurement (investigation). In Table 7, the Nd content, Ta content, Si content, and Mg content of Al-4Nd-2.0Ta- (Si, Mg) in the composition column are values in at% (atomic%). That is, Al-4Nd-2.0Ta-Z · Si (or Mg) contains 4.0 at% Nd and 2.0 at% Ta and an Al alloy containing Z at% Si (or Mg) [Al- Nd-Ta- (Si, Mg) alloy] thin film. For example, Al-4Nd-2.0Ta-5.0Si is an Al alloy containing 4.0 at% Nd, 2.0 at% Ta, and 5.0 at% Si.

  As can be seen from Table 7, the melting temperature decreases as the addition amount of Si and Mg increases. Further, by adding (containing) Si, the pitting corrosion occurrence potential is greatly increased, and the corrosion resistance is improved. Al-2.0Si (comparative example) is obtained by adding only Si, and no increase in pitting corrosion potential is observed. Both Si and Mg have the effect of reducing thermal conductivity, but the degree is low.

In the above example, either Nd or Y is added (single addition), and Cr to Nb, Ni (Cr, Ti , Mo, V, W, Zr, Hf, Nb, Ni) is One of them was added (single addition), but two types of Nd and Y were added (combination addition), and two or more of Cr to Nb and Ni were added (combination addition). Similar trend results are obtained.

  Since the Al alloy reflective film for optical information recording according to the present invention has a low thermal conductivity, a low melting temperature, and a high corrosion resistance, it can be suitably used as a reflective film for optical information recording that requires these characteristics. Can be suitably used as a reflective film for an optical information recording medium requiring laser marking.

It is a schematic diagram which shows the cross-section of a read-only optical disk.

1--polycarbonate substrate, 2--translucent reflective layer (Au, Ag alloy, Si), 3--adhesive layer,
4--Total reflection film layer (Al alloy), 5--UV curable resin protective layer.

Claims (5)

An Al alloy reflective film used for optical information recording media and laser-marked , containing Al as a main component, containing Nd and / or Y in an amount of 1.0 to 10.0 atomic%, and further Cr , Ti , Mo, V , W, Zr, Hf, Nb, Ni containing 0.5 to 5.0 atomic% of an Al alloy reflective film for optical information recording for laser marking . The Al alloy reflective film for optical information recording according to claim 1, wherein the content of Nd and / or Y is 2.0 to 7.0 atomic% . The Al alloy reflective film for optical information recording according to claim 1 or 2 , wherein the content of at least one of Cr, Ti, Mo, V, W, Zr, Hf, Nb, and Ni is 2.0 to 4.0 atomic% . The optical information recording medium characterized by having a Al alloy reflective film according to any one of claims 1-3. An Al alloy sputtering target used for optical information recording media and used for forming an Al alloy reflective film to be laser-marked, comprising Al as a main component, and containing Nd and / or Y at 1.0 to 10.0 atomic% And at least one of Cr , Ti , Mo, V, W, Zr, Hf, Nb, and Ni containing 0.5 to 5.0 atomic% of an Al alloy reflective film for optical information recording for laser marking . Al alloy sputtering target for forming.

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